Till now, various apparatuses for measuring pressure applied by an object against a sensor section and an amount of displacement thereof have been developed. In JP Laid-open No. 9-113203, for example, a sensor using a differential transformer is disclosed. This sensor is designed to detect the relative amount of displacement between a core and a differential coil to thereby determine an amount of displacement of an object. Since each of the core and the differential coils has a thickness, respectively, it is difficult to comprise them in a thin sheet. Thus, it has been difficult to apply such a sensor to a pressure distribution detecting apparatus.
There are various types of pressure distribution detecting apparatuses for detecting pressure distribution by means of a thin sheet, which include the apparatus using a pressure-sensitive rubber, the apparatus using electrostatic coupling and so on. For example, a pressure detecting apparatus using a pressure-sensitive rubber is disclosed in JP Laid-open No. 57-100331. This pressure detecting apparatus is designed, e.g. for a purpose of conducting performance assessment tests on seats for automobiles use, to lay a pressure detecting apparatus made from a pressure-sensitive rubber sheet onto a seat to determine the pressure distribution. Besides, the pressure detecting apparatus utilizing electromagnetic coupling to be used for the same usage is disclosed in JP Laid-open No. 62-226030, for example. This apparatus is also designed to use a sensor formed in a sheet to determine pressure distribution.
Patent Document 1: JP Laid-open No. 9-113203
Patent Document 2: JP Laid-open No. 57-100331
Patent Document 3: JP Laid-open No. 62-226030